On 8 January 1907, President Theodore Roosevelt issued Executive Order 549 that established the present usage:
In order that there shall be uniformity in the matter of designating naval vessels, it is hereby directed that the official designation of vessels of war, and other vessels of the Navy of the United States, shall be the name of such vessel, preceded by the words, United States Ship, or the letters U.S.S., and by no other words or letters.
United States Navy Regulations, 1990, Article 0406 defines the classification and status of naval ships and craft:
- The Chief of Naval Operations shall be responsible for ... the assignment of classification for administrative pur- poses to water-borne craft and the designation of status for each ship and service craft. ....
- Commissioned vessels and craft shall be called "United States Ship" or "U.S.S."
- Civilian manned ships, of the Military Sealift Command or other commands, designated "active status, in service" shall be called "United States Naval Ship" or "U.S.N.S."
- Ships and service craft designated "active status, in service," except those described by paragraph 3 of this article, shall be referred to by name, when assigned, classification, and hull number (e.g., "HIGH POINT PCH-1" or "YOGN-8").